378 RETROGRESSIVE CHANGES 



bounds." Likewise leukemia has been observed several times in 

 roentgenologists, presumably produced in the same way.®^ 



As the metabolic changes produced by rc-rays indicate an extremely 

 high rate of autolysis, one may ascribe the effects either to a stimulat- 

 ing effect of .T-rays upon autolytic enzjanes, or as Neuberg^^ does, to 

 an inhibitive action of a;-rays and radium rays upon the other intra- 

 cellular enzymes without a corresponding deleterious effect upon the 

 autolytic enzymes.^" This hypothesis agrees with the facts at hand, 

 bui more details concerning the effects of these rays upon various 

 enzymes are needed. The long latent period before the appearance 

 of necrosis after exposure to x-rays is difficult to explain^ and agrees 

 rather with the hypothesis of slow proliferative and obstructive 

 changes in the blood-vessels. 



Radium, which shares with x-rays the power of causing tissue 

 necrosis, does not have so marked an effect upon the blood, '^^ nor do 

 the ultra-violet rays (Linser and Helber).''^ In general, radium has 

 much the same effect on tissues as .r-rays,^^ but seems rather to stimu- 

 late the action of most enzymes ;^^ autolysis, however, is not increased 

 (Brown). '^^ Radium partially destroys the growth-promoting "vit- 

 amines" of yeast, which may account for some of its effects on tumors 

 (Sugiura and Benedict). Radium also causes severe skin lesions and 

 a general lymphocytosis in those exposed to it for long periods.''^ 

 Active deposit of radium emanation injected intravenously into 

 animals is highly toxic, even small doses causing fatty degeneration 

 in the liver associated with giant cell formation and hyperchromatic 

 nuclei; larger doses cause multiple hemorrhages and death with 

 severe enteritis. Lesions also occur in the kidneys, lungs, spleen and 

 bone marrow. '^^" In proper amounts radium stimulates plant meta- 

 bolism (Gager). Thorium-x also attacks specifically the leucocytes, ^^ 

 so that by proper dosage an animal may be made practically leucocyte- 

 s' See review by Wyss. Beitr. z. klin. Chir., 1906 (49), 185; Porter and Wol- 

 bach. Jour. Med. Res., 1909 (21), 357. 



«8 See Jagic and Schwarz, Berl. klin. Woch., 1911 (48), 1220. 



«9 Zeit. f. Krebsforschung, 1904 (2), 171; also Meyer and Bering, Fortschr. 

 Roentgenstrahlen, 1911 (17), 33; Richards, Amer. Jour. Physiol., 1914 (36), 400. 



'" Some authors have believed certain of the effects of .r-rays to be produced 

 by choline liberated through the decomposition of lecithin. (See Benjamin and 

 Reuss, Munch, med. Woch., 1906 (53), 1860.) 



'1 See Millet and Mueller, Jour. Cancer Res., 1918 (3), 127. 



^2 Deut. Arch. kUn. Med., 1905 (83), 479. 



'3 Review by Guyot, Cent. allg. Path., 1909 (20), 243; also see Mills, Lancet 

 1910 (179), 462; Richards, Science, 1915 (42), 287. Full bibliography by Sugiura 

 and Benedict, Jour. Biol. Chem., 1919 (.39), 421. 



7^ Loewenthal, Berl. klin. Woch., 1910 (47), 287; Kionlca, Med. Klinik, 1911 

 (7), 68.5. Denied by Gudzent, Zeit. Strahlenther., 1914 (4), 666. 



'6 T. R. Brown, Arch. Int. Med., 1912 (10), 405. 



" See Ordway, .lour. Amer. Med. Assoc, 1916 (66), 1. 



'*"Bagg, Jour. Cancer Res., 1920 (5), 1. 



" See Plesch et al, Zeit. exp. Path., 1912 (12), No. 1; Schweizer, Miinch. med. 

 Woch., 1916 (63), 341. 



